Wind tunnel investigations of the effectiveness of leading-edge flow control devices on non-slender delta wings

Wind tunnel experiments were conducted in order to investigate the effectiveness of flow control devices for a non-slender delta wing. Main objective of testing was to determine the effect on the rolling moment of different modifications of the left leading edge. As a clean configuration a flat delta wing model with round leading edges and a sweep angle of Λ = 53° was used. All tests were conducted in the open test section of a 1.00 × 0.70 m2 lowspeed atmospheric wind tunnel at Reynolds numbers from Re ≈ 0.3·106 up to Re ≈ 1.2·106. The angle of attack was varied from α = 0° to α = 34°. Modifications and actuators tested include wedges placed on the lee side of the wing right after the leading edge, a flat bar projecting out of the round leading edge (static and oscillating), a rotatable cylinder having a straight edge milled into its surface (replacing the round leading edge), and a plasma actuator. Forces and moments were obtained by a 6-component strain gauge and surface flow topologies by oil flow visualization. In certain cases also the vortical flow field above the surface was visualized by smoke and the velocity field determined by particle image velocimetry. Results obtained with the various flow control configurations will be presented and discussed